Molded casing, mold assembly and forming method

ABSTRACT

A molded casing suitable for a handheld electronic device is provided. The handheld electronic device includes a body and the molded casing, and at least one part of the body is covered with the molded casing. The molded casing is in a uniform thickness and has a continuous mosaic surface. The mosaic surface is composed of a plurality of non-coplanar polygons, wherein an intersection line is formed between any two adjacent polygons. An end of any one of the intersection lines is connected to an end of another intersection line or an edge of the mosaic surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of and claims the prioritybenefit of application Ser. No. 13/863,389, filed on Apr. 16, 2013, nowallowed. The entirety of the above-mentioned patent applications ishereby incorporated by reference herein and made a part of thisspecification.

FIELD OF THE INVENTION

The disclosure generally relates to a molded casing and themanufacturing technique thereof. More particularly, the disclosurerelates to a molded casing having a polygonal mosaic surface and themanufacturing technique thereof.

DESCRIPTION OF RELATED ART

Manufacture of a molded casing usually adopts injection moldingtechnology to inject elastic material into a mold, such that the surfacestructure of the mold is molded on a surface of the formed component, soas to facilitate fast and mass production.

To form the surface structure of the mold, the conventional methodsusually use the cutting tool of the machine tool to form the surface ofthe mold, or use the discharging electrodes of the electrical dischargemachining to melt the surface of the mold, so as to form the structuredescribed above on the surface of the mold.

However, the mold integrally formed by the methods described above ishard to provide an ideally molded structure due to manufacture limit ofmanufacturing apparatus or precision limit of trimming surfaces of thecutting tool. Specifically, in manufacture of the molded casing having apolygonal mosaic surface, it is known that the mold is hard to form astructure with sharp edges, such that the crest lines and the valleylines of the mosaic surface of the molded casing formed by the moldwould have round corners, and fail to meet the appearance requirement.

SUMMARY OF THE INVENTION

The present disclosure provides a molded casing having a mosaic surfacecomposed of a plurality of polygons, and an equivalent radius of avertex angle at each intersection line of the mosaic surface is close tozero, such that the mosaic surface of the molded casing has a pluralityof sharp crest lines and valley lines, and meet the appearancerequirement.

According to one embodiment of the present disclosure, the molded casingis suitable for a handheld electronic device, wherein the handheldelectronic device includes a body and the molded casing, and at leastone part of the body is covered with the molded casing. The moldedcasing is in a uniform thickness. The molded casing has a mosaicsurface, which is a continuous surface. The mosaic surface is composedof a plurality of non-coplanar polygons, wherein an intersection line isformed between any two adjacent polygons. An end of any one of theintersection lines is connected to an end of another intersection lineor an edge of the mosaic surface.

To make the above features and advantages of the present disclosure morecomprehensible, several embodiments accompanied with drawings aredescribed in detail as follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a perspective view of a front side of a moldedcasing according to one embodiment of the present disclosure.

FIG. 1B illustrates a perspective view of a back side of the moldedcasing in FIG. 1A.

FIG. 2A and FIG. 2B illustrate a process of molding a plate by a moldassembly to form a molded casing.

FIG. 3 illustrates a mold structure according to one embodiment of thepresent disclosure.

FIG. 4 further illustrates a cross-sectional view of a molded casingtaken out of the mold assembly in FIG. 2B.

FIG. 5 illustrates an example of a handheld electronic device adoptingthe molded casing of the present disclosure as a back cover.

DESCRIPTION OF EMBODIMENTS

FIG. 1A illustrates a perspective view of a front side of a moldedcasing according to one embodiment of the present disclosure. FIG. 1Billustrates a perspective view of a back side of the molded casing inFIG. 1A. Referring to FIG. 1 and FIG. 2, the molded casing 100 of thepresent embodiment is in a uniform thickness t1, and the front surfaceof the molded casing 100 is a mosaic surface 110, which is a continuoussurface. The mosaic surface 110 is composed of a plurality ofnon-coplanar polygons 120, and an intersection line 122 is formedbetween any two adjacent polygons 120. Each of the intersection lines122 may be a crest line or a valley line according to the included anglebetween the surfaces of the two adjacent polygons 120. In addition, thelengths of the adjacent sides of any two adjacent polygons 120 areequal. Therefore, an end 122 a of any one of the intersection lines 122on the mosaic surface 110 is connected to an end 122 a of anotherintersection line 122 or an edge 112 of the mosaic surface 110.

The polygons 120 composing the mosaic surface 110 may be triangles asshown in FIG. 1A, or other polygons such as quadrangle, hexagon, etc.Furthermore, the mosaic surface 110 may be composed of one type ofpolygons, for example, triangles, as shown in FIG. 1A, or composed of atleast two types of polygons. On the other hand, in the presentembodiment, an equivalent radius of a vertex angle at each intersectionline 122 may be set to be less than or equal to 0.1 millimeter, so as toform the sharp crest lines and valley lines on the molded casing. Themolded casing 100 is applicable to all kinds of products such ashandheld electronic device, so as to meet the requirement of molding andappearance, and be able to provide special visual effect.

The present disclosure further provides a method for forming the moldedcasing 100 described above. FIG. 2A and FIG. 2B illustrate a process ofmolding a plate 190 by a mold assembly 200 to form the molded casing100. Firstly, as shown in FIG. 2A, in the present embodiment, the moldassembly 200 includes a first mold 210 and a second mold 220, whereinthe first mold 210 and the second mold 220 respectively have a firstmosaic tooling surface 214 and a second mosaic tooling surface 224corresponding to the mosaic surface 110 of the molded casing 100described above, wherein the first mosaic tooling surface 214 and thesecond mosaic tooling surface 224 are opposite to each other and theshapes thereof are complementary to each other.

In the present embodiment, a plate 190 with uniform thickness isdisposed between the first mosaic tooling surface 214 of the first mold210 and the second mosaic tooling surface 224 of the second mold 220,and then the first mold 210 and the second mold 220 are compressed tomold the plate 190, wherein contours of the first mosaic tooling surface214 and the second mosaic tooling surface 224 are respectively molded onthe first surface 190 a and the second surface 190 b of the plate 190,so as to form the molded casing 100 having the mosaic surface 110described above. Afterward, the formed molded casing 100 is taken out ofthe mold assembly 200.

In the present embodiment, the plate 190 may be heated during thecompressing process described above to speed up the molding of the plate190. Herein, the temperature range of the heating process performed onthe plate 190 may be determined according to the material of the plate190 and other manufacturing conditions. In the present embodiment, thematerial of plate 190 may be, for example, glass, plastic, metal, etc.,and may be heated to a transition temperature, wherein the range of thetransition temperature is from 800° C. to 860° C. or from 500° C. to900° C.

In consideration of the conventional integrally-formed mold hard toprovide the ideally molded structure, the structure of the first mold210 and the second mold 220 are improved in the present embodiment, soas to provide the molded structure with sharp edges, so the mosaicsurface 110 of the molded casing 100 has sharp intersection lines 122.

FIG. 3 illustrates a mold structure 300 according to one embodiment ofthe present disclosure, which may be the first mold 210 or the secondmold 220 in FIG. 2A and FIG. 2B. The mold structure includes a pluralityof composition units 310, and each of the composition units 310 has asurface 312 in polygonal shape, for example, triangular, quadrilateralor other polygonal shape. The composition units 310 are arranged inparallel and adjacent to each other, such that the surfaces 312 of thecomposition units 310 form a mosaic tooling surface 320, which is acontinuous surface. Accordingly, a plurality of intersection lines 322are formed between any two adjacent surfaces 312 on the mosaic toolingsurface 320, and the lengths of the adjacent sides of any two adjacentsurfaces 312 are equal, such that an end 322 a of any one of theintersection lines 322 is connected to an end 322 a of anotherintersection line 322 or an edge 329 of the mosaic tooling surface 320.

The mold structure 300 is composed of a plurality ofmutually-independent composition units 310, such that the polygonalsurfaces 312 between any two adjacent composition units 310 are able toprecisely aligned and tightly connected to each other, so as to form themosaic tooling surface 320, and the formed mosaic tooling surface 320has sharp intersection lines 322.

In the present embodiment, the first mold 210 may adopt the design ofthe mold structure 300 described above. Namely, the first mold 210 mayinclude multiple first composition units 212 arranged in parallel on afirst base 282. Each of the first composition units 212 has a firstsurface 212 a, which is in polygonal shape, and the first compositionunits 212 are disposed adjacent to each other, and the first surfaces212 a tightly lean against to each other to form a first mosaic toolingsurface 214, which is a continuous surface. A first intersection line212 b is formed between any two adjacent first surfaces 212 a, and anend 212 c of any one of the first intersection lines 212 b is connectedto an end 212 c of another first intersection line 212 b or an edge 214a of the first mosaic tooling surface 214. Therefore, the first mosaictooling surface 214 may have sharp first intersection lines 212 b. Afterthe process shown in FIG. 2A and FIG. 2B, the contour of the firstmosaic tooling surface 214 is molded on the first surface 190 a of theplate, so as to form the mosaic surface 110 of the molded casing 100described above.

FIG. 4 further illustrates a cross-sectional view of the molded casing100 taken out of the mold assembly 200 shown in FIG. 2B. Referring toFIG. 4, the mosaic surface 110 of the molded casing 100 formed by thefirst mold 210 having the first mosaic tooling surface 214 with sharpfirst intersection lines 212 b would have sharp intersection lines 122corresponding to the first intersection lines 212 b. To be morespecific, an equivalent radius R1 of a vertex angle θ at eachintersection line 122 may be less than or equal to 0.1 millimeter, oreven close to zero, which is in no-rounded-angle condition.

On the other hand, FIG. 2A and FIG. 2B show that the second mold 220 islocated at a back side of the plate 190. Herein, the second mold 220 mayadopt the conventional design, which the second mold 220 is integrallyformed, or other method to form the second mosaic tooling surface 224,or may also adopt the design of the mold structure 300 in FIG. 3 to formthe second mosaic tooling surface 224 by a plurality of compositionunits. As shown in FIG. 2A and FIG. 2B, the second mold 220 includesmultiple second composition units 222 arranged in parallel on a secondbase 284. Each of the second composition units 222 has a second surface222 a, which is in polygonal shape, and the second composition units 222are disposed adjacent to each other, such that the second surfaces 222 aform the second mosaic tooling surface 224.

Furthermore, in another embodiment, a second mosaic tooling surface 224composed of a plurality of second surfaces 222 a may be, for example, aplane surface. For instance, the first mosaic tooling surface 214 of thepresent embodiment may be molded on the first surface 190 a of the plate190 to be a primary appearance surface, and the second mosaic toolingsurface 224 may be molded on the second surface 190 b of the plate 190to be a secondary appearance surface. Therefore, the present disclosuredoes not limit the second mosaic tooling surface 224 to a plane surfaceor a surface complementary to the first mosaic tooling surface 214,users may choose the manufacturing method of the second mosaic toolingsurface 224 according to actual demands of products.

FIG. 5 illustrates an example of a handheld electronic device adoptingthe molded casing of the present disclosure as a back cover. Referringto FIG. 5, a handheld electronic device 1 includes a body 10 and themolded casing 100 covering the back side of the body 10 as a back cover.Due to the equivalent radius R1 of the vertex angle θ, as shown in FIG.4, at each intersection line 122 on the molded casing 100 close to zero,the mosaic surface 110 having sharp crest lines and valley lines can beformed to meet the special requirement of molding and appearance, and beable to provide special visual effect.

Of course, the present disclosure does not limit the applications of themolded casing 100, which may be applied to other types of products, forexample, outer casings or decoration panels of electronic products suchas laptops, displays, etc., or home appliances and so on.

In sum, the mold assembly of the present disclosure uses a plurality ofmutually-independent composition units to form the mold, such that thepolygonal surfaces between any two adjacent composition units are ableto precisely aligned and tightly connected to each other to form themosaic tooling surface. Therefore, the mosaic tooling surface hascomparatively sharp intersection lines. Thereby, the molded casingformed by the mold assembly can have the mosaic surface with sharp crestlines and sharp valley lines, so as to meet the requirement for moldingand appearance, and be able to provide special visual effect.

Although the present disclosure has been described with reference to theabove embodiments, it will be apparent to one of ordinary skill in theart that modifications to the described embodiments may be made withoutdeparting from the spirit of the disclosure. Accordingly, the scope ofthe disclosure will be defined by the attached claims and not by theabove detailed descriptions.

What is claimed is:
 1. A molded casing, suitable for a handheldelectronic device, wherein the handheld electronic device comprises abody and the molded casing, at least one part of the body is coveredwith the molded casing, wherein the molded casing is in a uniformthickness, and has a continuous mosaic surface, the mosaic surface iscomposed of a plurality of non-coplanar polygons, an intersection lineis formed between any two adjacent polygons, and an end of any one ofthe intersection lines is connected to an end of another intersectionline or an edge of the mosaic surface.
 2. The molded casing as claimedin claim 1, wherein each of the polygons comprises triangle orquadrangle.
 3. The molded casing as claimed in claim 1, wherein themolded casing is a back cover of the handheld electronic device.
 4. Themolded casing as claimed in claim 1, wherein an equivalence radius of avertex angle at each intersection line is less than or equal to 0.1millimeter.
 5. The molded casing as claimed in claim 1, wherein any twoadjacent polygons of the mosaic surface are plane and oriented indifferent directions from each other.